Re: Spurious error on recursive invocation of fn:transform

xsl:copy doesn't feature in the original problem which instead uses
xsl:sequence

On Tue, Nov 24, 2020 at 7:08 PM Michael Kay <mike-JkSD5nQpfvpWk0Htik3J/[email protected]> wrote:

> Thanks, I've reproduced the problem. As expected, it's all to do with base
> URIs.
>
> I haven't got to the bottom of it yet, but I think the heart of the issue
> is that <xsl:copy> is creating a document whose base URI is defined to be
> the same as the stylesheet URI, and then we are using this URI as a key
> into the document cache for a call on doc(). Which ignores the fact that
> multiple documents can have the same base URI: the base URI is not a unique
> identifier for a document. Unfortunately the JAXP interfaces like the
> Source object and the URIResolver use a single property (systemId) to
> represent both base URIs and unique document URIs, so it's easy to get them
> mixed up.
>
> Michael Kay
> Saxonica
>
> On 24 Nov 2020, at 14:57, Ihe Onwuka <[email protected]> wrote:
>
>
> On Tue, Nov 24, 2020 at 7:32 AM Michael Kay <mike-JkSD5nQpfvpWk0Htik3J/[email protected]> wrote:
>
>>
>>> The usage of doc('') is not the causation here
>>
>> stylesheet-node :
>> doc('fullpathToTheStylesheetAsGeneratedWithdocument-uri/myStylesheet.xsl')
>>
>> the exact same result.
>>
>>
>>>
>> It's not so much the use of doc(""), as the reliance on preservation of a
>> base URI.
>>
>> Having said that, if you can put together a repro we'll be happy to look
>> at it. I think it's fairly clear the problem is happening because the base
>> URI is being lost through the call on fn:transform(), but whether losing it
>> is a bug or an application error is something we can only determine if we
>> study the detail.
>>
>> Michael Kay
>> Saxonica
>>
>
> Here.
>
> Here is bug.xsl
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>                 xmlns:fn="http://www.w3.org/2005/xpath-functions"
>        xmlns:xs="http://www.w3.org/2001/XMLSchema"
>        xmlns:local="urn:local"
> version="3.0" >
>
>    <xsl:mode on-no-match="shallow-copy"/>
>    <xsl:function name="local:generateNextVersion" as="document-node()">
>       <xsl:param name="currentVersion" as="document-node()"/>
>       <xsl:variable name="isFinalVersion" as="xs:boolean"
> select="$currentVersion/* eq '3'"/>
>       <xsl:sequence select="if ($isFinalVersion)
>                             then $currentVersion
>                             else
> local:generateNextVersion(fn:transform(map {
>
>  'stylesheet-node' : doc(''),
>                                                     'source-node'     :
>  $currentVersion
>                                                             })?output)"/>
>    </xsl:function>
>
>    <xsl:template match="*">
>   <xsl:message select="."/>
>       <xsl:copy>
>          <xsl:sequence select="let $customizedResult := fn:transform(map {
>
> 'stylesheet-node' :  doc('bugs2.xsl'),
>
> 'source-node'     :  /
>                                                                })?output
>                                return
>  local:generateNextVersion($customizedResult)"/>
>        </xsl:copy>
>    </xsl:template>
>
>  </xsl:stylesheet>
>
> Here is bugs2.xsl
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>                 xmlns:fn="http://www.w3.org/2005/xpath-functions"
> version="3.0" >
>
>    <xsl:mode on-no-match="shallow-copy"/>
>    <xsl:template match="*">
>       <xsl:copy>
>          <xsl:value-of select=". + 1"/>
>       </xsl:copy>
>    </xsl:template>
>
>  </xsl:stylesheet>
>
> Here is input XML
>
> <bug>1</bug>
>
> Reproduction instructions.
>
> Run the transform bug.xsl against input bug.xml and see the xsl:message
> output below
>
> <bug>1</bug>
> <bug>2</bug>
>
> Change bug.xsl to test for $currentVersion eq '4' instead of 3
>
> crashes as below
>
> <bug>1</bug>
> <bug>2</bug>
> Error in bugs2.xsl:
>   XTSE0150  The supplied file does not appear to be a stylesheet
> Static error in bugs2.xsl:
>   XTSE0150  The supplied file does not appear to be a stylesheet
> Error in bugs2.xsl:
>   XTSE0150  The supplied file does not appear to be a stylesheet
> at function local:generateNextVersion in bug.xsl:
>      invoked by function call
>   In template rule with match="*" of bug.xsl
>      invoked by built-in template rule (shallow-copy)
> The supplied file does not appear to be a stylesheet
>
>
>
>
>
>
>
>

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